Plasma sheet at lunar distance during magnetospheric substorms

Evidence is described from the charged particle lunar environment experiment (CPLEE) to support the thesis that the plasma sheet thins at the onset of a substorm and expands during substorm recovery in the region of X ranging from -60 to -15 earth radii. A comparison of substorm data from Vela 6A and CPLEE suggests that thinning does not occur simultaneously throughout the region but propagates as a 'thinning' wave as plasma is ejected from the near-earth region of the tail.